(a) Field of the Invention
The present invention relates to a stent or splint-like element for use in end-to-end nerve suture to eliminate tension at the anastomosis site and thus allow optimal coaptation between the nerve ends to be sutured.
The invention also relates to a method of carrying out end-to-end nerve suture, using such stent or splint-like elements to achieve maximum coaptation between the nerve ends.
The terms stent and splint-like are of the same meaning and may be interchanged hereafter.
(b) Description of the Prior Art
There are presently numerous techniques for use in nerve repairs, and more particularly for use in end-to-end nerve sutures.
Over the last decades, numerous improvements have been made to these techniques, in order, for example, to prevent irritation from the suture material, to achieve good coaptation of the nerve endings, to achieve bridging of nerve gaps with nerve grafts, to prevent stray regenerating nerve fibers and/or growth of fibrous scars, etc.
However, very few studies and suggestions have been made up to now in order to solve the major problem encountered by those practicing end-to-end nerve sutures, namely to eliminate tension at the anastomosis site.
By way of example, it is known that the suture technique known as "plasma clot method" and commonly used to perform sutureless nerve repair, cannot be carried out when there is tension at the suture site. With such a method, when there is some tension, coaptation cannot be achieved and nerve grafting is required.
It is also known that the technique known as "adhesive microanastomosis", which technique is carried out with an adhesive such as FIBRINE.RTM. or HISTOACRYL.RTM., cannot also be employed for nerve sutures when there is tension.
It is further known that most of the other existing techniques such as those known as "tubular splicing", "epineurial cuff neurorrhapy" or laser microanastomosis, are also very difficult to perform under tension.
It is therefore apparent that tension is and has always been a very important problem in nerve suture especially when considering that some degree of defect always exists between two nerve ends and that accordingly, it is almost impossible to avoid tension at the anastomosis site while matching the fasciculi.
To solve this problem, it has already been suggested to use very fine metal wire tension sutures. This technique however has proved not to be really satisfactory as such metal wires, that are rather big, can only be used to suture the adjacent lips of the epineurium of the nerve ends.
Since it is, in practice, almost impossible to achieve proper anastomosis under nerve tension, interfascicular nerve graft must usually be carried out to make it sure that there is no tension at the time of suturing the nerve ends. The results with nerve grafting however are always less than with nerve anastomosis is under no tension, because the graft nerve has to survive and the axons have to pass two anastomosis sites. Moreover, the amount of nerves to be used for such grafting is, in practice, limited.
Another technique to eliminate tension has been suggested by K. TSUGE et al under the name of "anchoring funicular sutures" (see K. TSUGE et al, Plast. Reconst. Surg., 56:496, 1975). This technique makes use of a needle fitted with a looped suture wire deviced for tendon suture. Basically, this technique consists of attaching the wire to the epineurium of one nerve end, then passing it through the epineurium of both nerve ends and subsequently tightening it and attaching it to the epineurium of the other nerve end in such a manner as to make to anastomosis site tension free.